Author: pfg
Date: Sat Jan 11 01:45:20 2014
New Revision: 260529
URL: http://svnweb.freebsd.org/changeset/base/260529
Log:
MFC r260361:
gcc: Fix optimization bug.
GCC-PR rtl-optimization/34628
* combine.c (try_combine): Stop and undo after the first combination
if an autoincrement side-effect on the first insn has effectively
been lost.
Modified:
stable/9/contrib/gcc/combine.c
Directory Properties:
stable/9/ (props changed)
stable/9/contrib/gcc/ (props changed)
Modified: stable/9/contrib/gcc/combine.c
==============================================================================
--- stable/9/contrib/gcc/combine.c Sat Jan 11 01:44:22 2014
(r260528)
+++ stable/9/contrib/gcc/combine.c Sat Jan 11 01:45:20 2014
(r260529)
@@ -2370,12 +2370,17 @@ try_combine (rtx i3, rtx i2, rtx i1, int
if (i1 && GET_CODE (newpat) != CLOBBER)
{
- /* Before we can do this substitution, we must redo the test done
- above (see detailed comments there) that ensures that I1DEST
- isn't mentioned in any SETs in NEWPAT that are field assignments. */
-
- if (! combinable_i3pat (NULL_RTX, &newpat, i1dest, NULL_RTX,
- 0, (rtx*) 0))
+ /* Check that an autoincrement side-effect on I1 has not been lost.
+ This happens if I1DEST is mentioned in I2 and dies there, and
+ has disappeared from the new pattern. */
+ if ((FIND_REG_INC_NOTE (i1, NULL_RTX) != 0
+ && !i1_feeds_i3
+ && dead_or_set_p (i2, i1dest)
+ && !reg_overlap_mentioned_p (i1dest, newpat))
+ /* Before we can do this substitution, we must redo the test done
+ above (see detailed comments there) that ensures that I1DEST
+ isn't mentioned in any SETs in NEWPAT that are field assignments.
*/
+ || !combinable_i3pat (NULL_RTX, &newpat, i1dest, NULL_RTX, 0, 0))
{
undo_all ();
return 0;
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